Integrate Turbolinks library

With this library included into FreedomBox UI, pages will load like on GitHub:

• Pages will load much faster because requests to various images, CSS, JS etc. will not happen.
• There will be a progress bar at the top showing the loading of the page.
• Load will be reduced on FreedomBox due to fewer requests.
• Nice animated page transitions can happen on Mobile screens.
• Fallback to nojs will be straightforward.

Implementation is easy:

• No need to implement special views for AJAX pages.
• Just include the library and do some Javascript settings.

Packaging of the library will be necessary.